refactor: implement thread-safe hardware operations, port caching, and refined state management in the device controller

tests/test_data_parser.py

@@ -242,6 +242,11 @@ class TestRemoveTrailingZeros:
         remove_trailing_zeros(data)
         assert len(data) == 2
 
+    def test_preserves_negative_temperatures(self):
+        data = [["25.0", "24.5"], ["-5.5", "-10.0"]]
+        remove_trailing_zeros(data)
+        assert len(data) == 2
+
 
 # ── save_to_csv ───────────────────────────────────────────────────────────────
 

tests/test_device_controller.py

@@ -87,31 +87,48 @@ def test_clear_session(controller):
     assert controller.selectedPort == ""
     assert controller.lastWaferInfo == ["", "", 0, "", 0, 0]
 
-def test_erase_memory(controller):
-    controller._service.erase_wafer = MagicMock(return_value=True)
+def test_erase_memory_spawns_thread(controller):
+    with patch("threading.Thread") as mock_thread:
+        controller.eraseMemory("COM1")
+        mock_thread.assert_called_once()
+        assert controller.operationInProgress
+
+def test_erase_memory_handler(controller):
     emitted_result = None
     def on_erase_result(result):
         nonlocal emitted_result
         emitted_result = result
 
     controller.eraseResult.connect(on_erase_result)
-    controller.eraseMemory("COM1")
+    controller._handle_erase_finished(True)
     assert emitted_result == {"success": True}
     assert controller.connectionStatus == "Connected"
+    assert not controller.operationInProgress
 
-def test_read_debug(controller):
-    controller._service.read_wafer_data = MagicMock(return_value=bytes([12] * 512))
+def test_read_debug_spawns_thread(controller):
+    with patch("threading.Thread") as mock_thread:
+        controller.readDebug("COM1")
+        mock_thread.assert_called_once()
+        assert controller.operationInProgress
+
+def test_read_debug_handler(controller):
     emitted_result = None
     def on_debug_result(result):
         nonlocal emitted_result
         emitted_result = result
 
     controller.debugResult.connect(on_debug_result)
-    controller.readDebug("COM1")
+    controller._handle_debug_finished({
+        "success": True,
+        "sensor_bytes": 512,
+        "debug_bytes": 512
+    })
     assert emitted_result is not None
     assert emitted_result.get("success") is True
     assert emitted_result.get("sensor_bytes") == 512
     assert emitted_result.get("debug_bytes") == 512
+    assert controller.connectionStatus == "Connected"
+    assert not controller.operationInProgress
 
 def test_parse_and_save_data_and_get_chart_data(controller):
     res = controller.getChartData()
@@ -187,3 +204,29 @@ def test_detect_wafer_clears_old_session(controller):
         assert len(controller._activity_log) == 1
         assert "Scanning all ports" in controller._activity_log[0]
 
+def test_device_service_port_caching(controller):
+    service = controller._service
+    # Mock comports list
+    with patch("serial.tools.list_ports.comports", return_value=[]), \
+         patch("subprocess.run") as mock_run:
+        # Mock subprocess to return empty
+        mock_run.return_value.returncode = 0
+        mock_run.return_value.stdout = ""
+
+        # Clear cache first
+        service.clear_port_scan_cache()
+
+        # First scan should invoke list_ports and subprocess
+        ports1 = service.enumerate_ports()
+        assert mock_run.call_count == 1
+
+        # Second scan within 2 seconds should return cached list without invoking subprocess
+        ports2 = service.enumerate_ports()
+        assert mock_run.call_count == 1
+        assert ports1 == ports2
+
+        # Clear cache and scan again should invoke subprocess
+        service.clear_port_scan_cache()
+        ports3 = service.enumerate_ports()
+        assert mock_run.call_count == 2
+